The present disclosure is directed towards coatings, and more particularly towards a coating including antimicrobial agents for use in medical applications.
There has been research conducted in the area of coatings incorporating antimicrobial agents. Certain of the research has been directed towards coatings involving active release strategies. Antibiotics, silver ions, and antiseptics, have been among the antimicrobial agents studied.
In the area of antimicrobial coatings for medical devices, whether for short term use or long term permanent implants, many scientific publications refer to their use in connection with central venous catheters, urinary tract catheters and penile prostheses. A particular combination of two antibiotics, Rifampin and Minocycline, has been shown to successfully reduce biofilm colonization on these specific devices.
A number of methods to coat silicone surfaces of medical devices have also been previously studied. In one known approach, impregnation of a device with antibiotics dissolved in a swelling agent was employed. In other approaches, coatings involved application of a film of silicone oil followed by antimicrobial agents in a powder form or a graft-polymerization of a coating incorporating a drug. In yet another approach, a hydrophilic polymer containing antibiotic ceramic particles was utilized.
Many of these methods and approaches can be classified as “surface coatings” since only the surface of the device is coated by antibiotics. However, another method designed to promote the penetration of the antimicrobial agents throughout the volume of the device (“impregnation”) is also known.
These methods and other related approaches published in the literature or reported in patents can suffer from a number of limitations. In some cases, the coating is superficial (“surface coating”), thereby providing only a short time of effective protection against bacteria following the initial burst release of the active drug. Moreover, when the “impregnation” method is used, the advantage of an extended period of antimicrobial efficacy is achieved by incorporating the drug into the volume of the device by swelling the material forming the device (for example silicone) and subsequently physically trapping the active substance within. However, this often requires a large amount of drug, most of which will not become available at the surface and will remain in the bulk of the device given the high affinity of the drugs for the device material. Also, swelling finished devices to incorporate drugs may have undesired effects on their mechanical properties or it may introduce unwanted volatile residues within the composition (for example a gel). This is particularly true with long term or permanent prostheses such as breast implants.
Accordingly, there is a need for a coating with an antimicrobial agent that can be used in connection with a medical device while providing extended effective protection without requiring a large amount of drugs to accomplish desired protection. The present disclosure addresses these and other needs.